Heater Door
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Do you have the C60 manual HVAC system or the C68 digital HVAC system?
You say "heater door". Do you mean the temperature blend door? It changes the air flow through the ducts to either go through the heater core or not.
You say "heater door". Do you mean the temperature blend door? It changes the air flow through the ducts to either go through the heater core or not.
Thread Starter
Instructor
Joined: Apr 2006
Posts: 204
Likes: 0
From: Wilbraham Mass.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The blend door is moved by a motor that is controlled by the HVAC programmer. The HVAC programmer is mounted on the firewall above the gas pedal.
You can check the operation of the blend door motor by removing and replacing the CTSY/CLK fuse. That will erase the settings in the HVAC control head. Remove the blower control module mounted on the top of the evaporator housing. That will allow you to see the blend door. Turn on the ignition and the HVAC controller will calibrate the blend door by moving it to the maximum heat position and the maximum cool position and then it will move it to the position corresponding to the temperature set on the HVAC control head. The calibration takes about 15 seconds and you can watch it through the blower control module opening.
You can also check the blend door by setting the temperature to 60° (maximum cool). The blend door should look like this:
Set the temperature to 90° (maximum heat) and it should look like this:
If it moves to one of the above positions but not the other one then you probably have a burned resistor or bad solder connection on the HVAC programmer. The resistors that do the blend door positioning are in the lower left corner of this picture (they get hot and burn the PC board, which is why that area is discolored):
It is also possible that one of the transistors that operate the blend door motor on the HVAC programmer is bad.
You can check the operation of the blend door motor by removing and replacing the CTSY/CLK fuse. That will erase the settings in the HVAC control head. Remove the blower control module mounted on the top of the evaporator housing. That will allow you to see the blend door. Turn on the ignition and the HVAC controller will calibrate the blend door by moving it to the maximum heat position and the maximum cool position and then it will move it to the position corresponding to the temperature set on the HVAC control head. The calibration takes about 15 seconds and you can watch it through the blower control module opening.
You can also check the blend door by setting the temperature to 60° (maximum cool). The blend door should look like this:
Set the temperature to 90° (maximum heat) and it should look like this:
If it moves to one of the above positions but not the other one then you probably have a burned resistor or bad solder connection on the HVAC programmer. The resistors that do the blend door positioning are in the lower left corner of this picture (they get hot and burn the PC board, which is why that area is discolored):
It is also possible that one of the transistors that operate the blend door motor on the HVAC programmer is bad.
Thread Starter
Instructor
Joined: Apr 2006
Posts: 204
Likes: 0
From: Wilbraham Mass.
The blend door is moved by a motor that is controlled by the HVAC programmer. The HVAC programmer is mounted on the firewall above the gas pedal.
You can check the operation of the blend door motor by removing and replacing the CTSY/CLK fuse. That will erase the settings in the HVAC control head. Remove the blower control module mounted on the top of the evaporator housing. That will allow you to see the blend door. Turn on the ignition and the HVAC controller will calibrate the blend door by moving it to the maximum heat position and the maximum cool position and then it will move it to the position corresponding to the temperature set on the HVAC control head. The calibration takes about 15 seconds and you can watch it through the blower control module opening.
You can also check the blend door by setting the temperature to 60° (maximum cool). The blend door should look like this:
Set the temperature to 90° (maximum heat) and it should look like this:
If it moves to one of the above positions but not the other one then you probably have a burned resistor or bad solder connection on the HVAC programmer. The resistors that do the blend door positioning are in the lower left corner of this picture (they get hot and burn the PC board, which is why that area is discolored):
It is also possible that one of the transistors that operate the blend door motor on the HVAC programmer is bad.
You can check the operation of the blend door motor by removing and replacing the CTSY/CLK fuse. That will erase the settings in the HVAC control head. Remove the blower control module mounted on the top of the evaporator housing. That will allow you to see the blend door. Turn on the ignition and the HVAC controller will calibrate the blend door by moving it to the maximum heat position and the maximum cool position and then it will move it to the position corresponding to the temperature set on the HVAC control head. The calibration takes about 15 seconds and you can watch it through the blower control module opening.
You can also check the blend door by setting the temperature to 60° (maximum cool). The blend door should look like this:
Set the temperature to 90° (maximum heat) and it should look like this:
If it moves to one of the above positions but not the other one then you probably have a burned resistor or bad solder connection on the HVAC programmer. The resistors that do the blend door positioning are in the lower left corner of this picture (they get hot and burn the PC board, which is why that area is discolored):
It is also possible that one of the transistors that operate the blend door motor on the HVAC programmer is bad.
